International Journal of Advanced Design and Manufacturing Technology
Volume:3 Issue: 2, 2010

This paper presents optimal control method to path planning of mobile robotswith flexible joints. Dynamic equations are derived and additional kinematic constraintsare used to solve the extra Dofs arose from base mobility. Then with modeling theelasticity at each joint as a linear torsinal spring, the set of equations are formed. TheHamiltonian function is formed and the necessary conditions for optimality are derivedfrom the Pontryagin''s minimum principle. The obtained equations established a two pointboundary value problem solved by numerical techniques. This problem is known to becomplex in particular when combined motion of the base and manipulator, non-holonomicconstraint of base and non-linear and complicated dynamic equations as a result of flexiblenature of joints are taken into account. The study emphasizes on modeling of the complete optimal control problem by remaining all nonlinear state and costate variables as well as control constraints to establish accompanying boundary value problem. Another advantage of this method is obtaining various optimal trajectories with different characteristics by changing the penalty matrices values which enables the designer to choose the best trajectory. A mobile flexible joint manipulator is studied to verify the feasibility of the proposed approach.

Recently, as the result of development in modern imaging, computerized threedimensional data processing and advanced engineering techniques, a prosthesis that matchthe skeletal anatomy can be accurately designed using computer aided design (CAD)where the physical model of prosthesis or skull replica can be produced through rapidprototyping (RP), rapid tooling (RT), and computer aided manufacturing (CAM)technology. This paper aims to describe CAD, CAM, RP systems and technologies fordesign and fabrication of custom-made hip prostheses. A novel methodology based on RPtechnology is applied to design and manufacture a custom-made hip prostheses. Resultsshow that the RP models provide an accurate and useful tool for preoperative, surgicalsimulation and fabrication of such prostheses. Concerning the disadvantages such as timeand cost for the hip prostheses design and need for surgical robot to perform the boneresection and preparing proper femoral canal, RP technologies fabricate the custom-madeprostheses quickly, accurately and economically.

Shape error due to elastic recovery of formed part in unloading known asspringback، is one of the most important problems of tool design in sheet metal formingprocesses. Many researches have been performed for proposing an efficient method todecrease or compensate springback error in sheet forming processes. These methods areusually based on iterative finite element algorithms. In this paper an analytical approach ispresented for one step modification of the tooling shape in channel forming process tocompensate the springback error. With the help of this approach، the optimum die shapefor producing the target shape can be obtained in a few seconds. The algorithm ofspringback compensation by inverse FE modelling is also presented. By balancing thecontact forces in this algorithm، symmetric and asymmetric sheet forming processes can be analyzed. The results of the analytical approach coincide with those of FE approach. Theaccuracy of the obtained results is verified by the experimental results. Asymmetricchannel forming tests are performed on steel and aluminum sheets. The test resultscoincide to the analytical results with high precision.

Several approaches are available to reduce pulsating torque components inpermanent magnet motors. One of the known techniques is stator tooth shapemodifications. This paper presents an integrated algorithm applicable for tooth shapeoptimization of permanent magnet motors. This method focuses on the reduced basistechnique, finite element analysis and Taguchi method and is conducted on tooth shapeoptimization of a 3-phases radial flux PMSM motor.

Zn-Co electrodeposits have attracted interest because of their significantlyhigher corrosion resistance in comparison with pure zinc. In this research the influence ofbath temperature and electrolyte’s Co2+ concentration on the morphology and composition of the Zn-Co coatings, electrodeposited on an AISI1018 steel substrate from a weaklyalkaline glycine solutions, has been studied. SEM and EDS analysis were used to studysurface morphology and composition of Zn-Co alloy coatings. It was shown that byincreasing the bath temperature and Co2+ concentration in electrolyte, the cobaltconcentration in the coating was increased. By increasing the cobalt concentration in thebath favoring the formation of smaller grains; however further increase of cobalt in thebath resulted in coarsens the morphology of the coating.

A truly meshless local Petrov-Galerkin (MLPG) method is developed forsolving 3D elasto-static problems. Using the general MLPG concept, this method isderived through the local weak forms of the equilibrium equations, by using test functions,namely, the Heaviside function. The moving least squares (MLS) are chosen to constructthe shape functions, for the MLPG method. The penalty approximation is used to imposeessential boundary condition. Several numerical examples are included to demonstrate thatthe present method is very promising for solving the elastic problems.

Rapid thermal processing (RTP) has become a key technology forsemiconductor device manufacturing in a variety of applications، such as thermaloxidation، annealing، and thin-film growth. Hence، understanding the radiative propertiesof silicon and other relevant materials is essential for the analysis of the thermal transportprocesses. We have analyzed and calculated the spectral، directional and temperaturedependency of radiative properties of a three layers material using transfer-matrix method. In the present work empirical expressions for calculating the optical constants of materialsare carefully selected. The studied examples using silicon wafer and either silicon dioxideor silicon nitride coating demonstrate the strong influence of coating and coating thicknesson the radiative properties. This study helps to gain a better understanding of the radiative properties of semitransparent wafers with different coatings and will have an impact notonly on semiconductor processing but also on thin film solar cells. Results showed that silicon dioxide coating has higher reflectance than silicon nitride coating for visible wavelengths. Therefore coatings act as wavelength selective emitters for radiative energy conversion and thermal radiation detection. In visible wavelengths the reflectanceincreases as the temperature increases، because of decreasing emittance but in infraredwavelengths the reflectance and transmittance decrease as the temperature increases. The layer thicknesses need to be optimized to achieve maximum transmittance for the given materials. Maximum transmittance also depends on the type of materials and itstemperature.

This paper defines how a meta heuristic search engine called P.S.O can be usedto maximize the objective function of a logistic regression model, describing therelationship between the response variable (product designs'' score) and a set ofexplanatory variables (product design factors). At the first phase the processed data,classified and categorized, by Kansie Engineering is used as input to the logistic regressionmodel. The PSO optimization algorithm, maximizes the likelihood function, thus theparameters of the model, being the coefficients of the independent factors are estimated.After post hoc tests, the validated model, defines the relation between consumer semanticand physical product selection factors and the response variable which is a dichotomous dependent ordered variable representing product design scores.